Assessment of multi-elemental concentrations in various tea types cultivated in Vietnam

Abstract

     Tea (Camellia sinensis L.) has been considered the second most popular non-alcoholic beverage in the world. Tea has high nutritional and medicinal values because it contains not only various antioxidant compounds, amino acids but also many essential macro-nutrients and micro-nutrients. In this study, the inductively coupled plasma-mass spectrometry (ICP-MS) was validated and applied to evaluate the release of elements, including macro-nutrients, micro-nutrients and non-essential elements in tea infusions prepared with various brewing temperatures and durations. The results showed that the increase in the brewing water temperature played a more important role in rising the percentage of element released into the infusion than lengthening the infusion durations at the brewing temperature of 70 ⁰C. The release percentages of the micro-nutrients gradually decreased in the order of B > Mn > Zn > Cu > Fe > Ni, in which Fe and Ni exhibited their lower values compared to other elements. The highest Al concentration in tea water was recorded in red tea samples (approximately 2,5 mg/L), under the permitted limits of WHO.